DHB1500 combines the core composition of MetroGain™ with the bow-tie geometry of the HB range of fibers. It is invaluable in mode-locked fiber lasers or in any specialised EDFAs that demand polarisation maintenance. The standard specification enables polarisation extinction ratios of up to -30 dB to be achieved over typical gain lengths of 8 - 14 metres under normal packaging conditions with amplifier performance closely matching that of MetroGain™ 5. DHB1500 is designed for 980 nm pumping.